Self-priming centrifugal pump

ABSTRACT

A centrifugal pump is described wherein the pumping face of the impeller is disposed vertically and wherein integral self-priming means are provided.

United States Patent Rule [ 51 Oct. 3, 1972 [54] SELF-PRIMINGCENTRIFUGAL PUMP [72] Inventor: Clinton Rule, Leather Lane, Mass. 0191?Mass.

[22] Filed: Oct. 16, 1970 [21] App1.No.: 81,226

[52] US. Cl ..415/206, 417/199 A, 415/121 [51] Int. Cl. ..F04d l/00,F04d 9/00 [58] Field of Search ..415/53, 206, 204, 121;

[56] References Cited UNITED STATES PATENTS 2,008,308 7/1935 Jacobsen..415/53 Assignee: Rule Industries, Inc., Gloucester,

2,166,358 7/1939 La Bout ..415/53 2,627,817 2/1953 Mann et a1 ..415/532,755,743 7/1956 Rupp ..415/53 FOREIGN PATENTS OR APPLICATIONS 55,57410/1943 Netherlands ..415/53 I Primary Examiner1-lenry F. RaduazoAttomey-William N. Anastos ABSTRACT A centrifugal pump is describedwherein the pumping face of the impeller is disposed vertically andwherein integral self-priming means are provided.

4 Claims, 2 Drawing Figures SELF-PRIMING CENTRIFUGAL PUMP Impeller pumpscan generally be conveniently grouped into two broad design categories:Those in which the pumping face of the impeller is disposed horizontallyand those in which the pumping face of the impeller is disposedvertically. The latter type, i.e., that type wherein the pumping 'faceof the impeller is disposed vertically, shall be referred to hereinafteras side-impeller pumps, and it is to said side-impeller pumps that thepresent invention principally relates.

In a side-impeller pump, the impeller rotates around a horizontalcenterline within the impeller chamber. A major advantage generallyenjoyed by pumps of this type resides in their generally lower profileor height for a given liquid pumping capacity. According, suchside-impeller pumps are often especiallyadaptable for use in locationswhere vertical space is at a premium, such as, for example, under thefloorboards of a small boat.

However, one of the major disadvantages of side-impeller pumps residesin their tendency to lose their prime subsequent to each operatingcycle. This detrimental tendency is often an important concern whichlimits employment.

Methods and means for repriming and/or avoiding loss of prime fromside-impeller pumps are of course known. For instance, one methodcomprises maintaining such pumps substantially completely submergedbeneath the surface of the liquid to be pumped, thereby avoiding loss ofprime. However, the use of this method requires that a substantial levelof liquid be maintained in the area to be pumped, which level isfrequently undesirably high.

Mechanical repriming and/or prime loss avoidance means are also knownbut are generally either complex and impractical and/or separate anddistinct from the pump. These features tend to mitigate against theiruse. Moreover, those means which serve the sole function of repriming apump after loss of prime are frequently not automatic, and thus requirethe manual attention of an operator prior to or during each operationalcycle of the pump.

In accordance with the present invention, however, the above and otherproblems heretofore associated with prior art side-impeller pumps and/orauxiliary repriming means therefor have been substantially completelyresolved.

It is a principal object of the invention to provide novel self-priming,side-impeller pumps.

It is yet another object of the invention to provide self-priming meansfor side-impeller pumps which means are characterized by theirresistance to fouling.

It is another object of the invention to provide improved side-impellerpumps having integral self-priming means.

It is still another object of the invention to provide a self-priming,side-impeller bilge pump having substantial resistance to loss of primedue to rolling or listing of the hull in which said pump is mounted.

Other objects and advantages of the invention will in part be obviousand will in part appear hereinafter.

In accordance with the present invention, it has been discovered thatself-priming of side-impeller pumps is achieved by providing a liquidreservoir in open communication with the impeller chamber, whichreservoir is supplied by a circuitous ascending and descending conduitmeans interposed between said reservoir and the liquid intake.

FIG. 1 is a schematic isometric partly in section of the pump prior tothe attachment of the priming reservoir of the present invention.

FIG. 2 is the priming reservoir of the present invention with interiorexposed.

Referring now to the drawing, there is illustrated a side-impeller pumpgenerally comprising a housing 3 which contains therein a prime moversuch as a horizontally mounted, conventional, small, electric motor (notshown). In order to maintain the prime mover out of contact with theliquid to be pumped (which is frequently desirable), housing 3 isconventionally liquid-tight. Drive shaft 5, in operative relationshipwith the prime mover, penetrates partition 7 of housing 3 into impellerchamber 9. In order to maintain the liquid-tight integrity of housing 3,an appropriate shaft seal or packing (not shown) is preferably providedin association with the penetration of shaft 5 through partition 7.Impeller 11 is mounted on shaft 5 coaxially within impeller chamber 9.The perimeter of impeller chamber 9 is defined by casing 13, while theend closures of said chamber are constituted by partition 7 and endplate15.

Discharge of liquid from impeller chamber 9 is accomplished throughtangential conduit 17 which is in open communication with the upperportions of said chamber. Liquid input into chamber 9 is achievedthrough inlet orifice 19 in endplate l5, orifice 19 being preferablylocated at the eye of the impeller, i.e. substantially concentricallywith respect to shaft 5. Upon appropriate activation, therefore,impeller 11 is rotated by drive shaft 5 which, in turn, is rotated bythe prime mover. Liquid is drawn into impeller chamber 9 through orificel9 and is discharged through conduit 17. Upon deactivation, and as istypical of side-impeller pumps, impeller chamber 9 tends to largelyempty itself of liquid due to gravity or siphon backflow of liquidthrough orifice 19. While liquid will ordinarily be retained in liquidtight impeller chamber 9 below the level of orifice 19, designated aslevel A in the drawing, the loss of liquid experienced from the upperportions of chamber 9 often results in loss of prime. As a result,unless the ambient liquid level about the pump builds up prior to thesucceeding operating cycle to at least the top of orifice 19 designatedas level B in the drawing, and often to level C, said subsequentoperating cycle frequently fails to pump liquid because of failure ofthe pump to be sufficiently primed.

Prior art methods for remedying the loss of liquid from the impellerchamber have conventionally involved the use of check valves, ballvalves and the like which are installed at some point between the liquidintake port of the pump and orifice 19. Such valves are intended toclose upon deactivation of the pump thereby avoiding to a substantialdegree the evacuation of impeller chamber 9. Unfortunately, however,these valves often foul when the liquid to be pumped is not perfectlyclean. For example, the bilge water in boats normally containssubstantial quantities of particulate and other fouling matter, thusmitigating heavily against the use of check valves.

In the self-priming, side-impeller pumps of the present invention,however, such fouling problems are substantially circumvented. Forpurposes of clarity, the self-priming means of the invention is shown inthe drawing disassembled from the major portion of the pump describedhereinabove. Said means generally comprises liquid intake 20, ascendingconduit 22, transverse conduit 28 and descending conduit 24, theterminus of conduit 24 being a reservoir 35, which reservoir is in opencommunication with orifice 19 when the unit is assembled. It should beunderstood that while the self-priming means of the invention is shownas a continuous open channel and reservoir, partitions 26 on endplate 30defining said channel and reservoir when the entire unit is assembled,as indicated by the dotted lines, must abut endplate in liquid tightrelationship and so as to provide a closed reservoir and a circuitous,at least partially vertical, path from intake 20 to orifice l9.

Transverse (:onduit 28 is, strictly speaking, necessary only to conductliquid from ascending conduit 22 into descending conduit 24.Accordingly, if desired, a suitable alternative to the presence of saidtransverse conduit 28- resides in a more direct connection of ascendingconduit 22 to descending conduit 24 such as an inverted V or loop at theapex of said ascending conduit 22. The presence of transverse conduit 28together with a vertical partition 32 of some sort on conduit 28 is,however, preferred as will be explained in more detail hereinafter.

With regard to the design criteria of descending conduit 24 andreservoir 35, it is all important that as a whole they retain sufficientliquid between operating cycles of the pump to ensure priming of thepump upon start up. The absolute minimum volume of said retained liquidshould represent the difference between the full liquid volume ofimpeller chamber 9 and the normally retained liquid volume thereof whenidle. As mentioned previously, the volume of liquid lost from chamber 9in prior art pumps ordinarily brings the level in chamber 9 down toabout level A in the drawing. However, in the present invention,reservoir 35 is designed so as to be in open communication with orificel9 and to prevent the loss of liquid in chamber 9 below about level B.

Nevertheless, even with this minimum quantity of liquid in chamber 9,loss of prime can result, and it is the further role of reservoir 35 toretain enough additional liquid to substantially ensure successfulpriming. The total quantity of liquid required as a minimum tosubstantially ensure successful priming is extremely difficult topredict due to the many variables at work. The volumes of conduits 22and 28 are important factors, for example. Typically, the greater thevolumes of conduits 22 and 28, the greater will be the quantity of waterthat must be stored in reservoir 35 to ensure successful priming. Ingeneral, the minimum quantity of liquid stored in reservoir 35 should atleast equal the volume, and most preferably should equal 1.5 times thevolume, of conduits 22 and 28 expanded to a pressure which is less thanatmospheric by at least the length of conduit 22 in inches of the fluidto be pumped. If this minimum quantity of water is present in reservoir35 upon start up of the pump, atmospheric pressure will tend to forcewater up conduit 22, through conduit 28 and thence into reservoir 35thereby tending to substantially ensure successful priming. To this end,therefore, it is greatly preferred that reservoir 35 comprise lateralportions 36 which substantially increase the volume of liquid that canbe retained. Moreover, the use of lateral chambers 36 to form aninverted T- shaped reservoir also serves to minimize the potential lossof availability of liquid to chamber 9 due to rolling and/or pitching ofthe boat as frequently occurs in bilge pump applications. While thevolume of reservoir 35 can also be increased by increasing the front toback depth thereof, it should be borne in mind that the use of thatdesign expedient will also tend to increase the overall length of thepump apparatus.

Also, the positioning of partition 32 (if there is one) is important.Said partition can serve to break a siphon action that may develop upondeactivation of the pump, which siphon action may empty or reduce thelevel of liquid in reservoir 35.

Other considerations include the height of chamber 35. Chamber 35 shouldbe about as high as level B so that chamber 9 will always be full to atleast that level. if the height of chamber 35 were greater than that,chamber 35 would contain air above about level B. lf said height werelower, chamber 35 would not be capable of maximum capacity.

Bottom partition 38 of reservoir 35 can, of course, be positionedsubstantially below level A. However, it should be recognized that insuch instances not all the liquid retained in reservoir 35 willordinarily be available to flow into chamber 9. Specifically, in suchinstances, only that liquid existing in reservoir 35 at above aboutlevel A can aid in priming the pump as only that liquid will normally beavailable to impeller chamber 9. When the entire pump is positionedother than horizontally, however, some of the liquid normally trappedbelow level A may enter chamber 9.

Attachment of endplate 30 bearing the self-priming system to the pumpapparatus proper can be achieved in any suitable manner. Generallyspeaking, the particular manner of attachment will be dictated to alarge extent by the materials of construction employed. We have foundthat polymeric materials, particularly the thermoplastics such as ABS,are generally admirably suited for use as materials of construction. Insuch instances, attachment of the self-priming means of the invention tothe pump proper can be achieved by art recognized methods such assolvent welding, glueing, or the like, bearing in mind, of course, thatthe open channel means specifically illustrated in the drawing requiresthat edges 29 of partitions 26 be bonded in liquid-tight relationship toendplate 15. However, when other suitable materials such as variousmetals are employed as materials of construction, attachment to the pumpcan be effected by soldering or welding, or by mechanical means such asgasketing or sealing coupled with screws, rivets, etc.

Obviously many changes can be made in the above description and/ordrawing without departing from the scope of the present invention.Accordingly, it is intended not to limit the invention in any mannerexcept as defined in the claims.

What is claimed is:

1. In a side-impeller, centrifugal liquid pump comprising a prime mover,a water-tight impeller chamber,

a shaft in operative relationship with said prime mover extending intosaid chamber, an impeller affixed to said shaft within said chamber, aninlet into said chamber positioned substantially concentrically withsaid impeller, and an outlet from said chamber, the improve- 5 mentwhich comprises providing a liquid reservoir outside said chamber but inopen communication by gravity flow with said inlet, and means connectedto the top portion of said reservoir by a circuitous path comprising avertical portion which downwardly from the top portion below the levelof said reservoir, and said reservoir having a capacity in part projects

1. In a side-impeller, centrifugal liquid pump comprising a prime mover,a water-tight impeller chamber, a shaft in operative relationship withsaid prime mover extending into said chamber, an impeller affixed tosaid shaft within said chamber, an inlet into said chamber positionedsubstantially concentrically with said impeller, and an outlet from saidchamber, the improvement which comprises providing a liquid reservoiroutside said chamber but in open communication by gravity flow with saidinlet, and means connected to the top portion of said reservoir by acircuitous path comprising a vertical portion which in part projectsdownwardly from the top portion below the level of said reservoir, andsaid reservoir having a capacity available to flow into said chamber atleast as great as the volume of said circuitous path.
 2. The pump ofclaim 1 wherein said reservoir has a capacity available to flow intosaid chamber at least 1.5 times as great as the volume of saidcircuitous path.
 3. The pump of claim 1 wherein said circuitous path isprovided with a siphon breaking means.
 4. The pump of claim 1 whereinsaid reservoir comprises lateral portions which increase the overallliquid capacity of said reservoir.